31 lines
476 B
ArmAsm
31 lines
476 B
ArmAsm
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.var ticket
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.var turn
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.var count
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.main
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.top
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.acquire
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mov $1, %ax
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fetchadd %ax, ticket # grab a ticket (keep it in dx)
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.tryagain
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mov turn, %cx # check if it's your turn
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test %cx, %ax
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jne .tryagain
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# critical section
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mov count, %ax # get the value at the address
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add $1, %ax # increment it
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mov %ax, count # store it back
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# release lock
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mov $1, %ax
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fetchadd %ax, turn
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# see if we're still looping
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sub $1, %bx
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test $0, %bx
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jgt .top
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halt
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